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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/ia64/lib/idiv64.S
downloadlinux-stericsson-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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+/*
+ * Copyright (C) 1999-2000 Hewlett-Packard Co
+ * Copyright (C) 1999-2000 David Mosberger-Tang <davidm@hpl.hp.com>
+ *
+ * 64-bit integer division.
+ *
+ * This code is based on the application note entitled "Divide, Square Root
+ * and Remainder Algorithms for the IA-64 Architecture". This document
+ * is available as Intel document number 248725-002 or via the web at
+ * http://developer.intel.com/software/opensource/numerics/
+ *
+ * For more details on the theory behind these algorithms, see "IA-64
+ * and Elementary Functions" by Peter Markstein; HP Professional Books
+ * (http://www.hp.com/go/retailbooks/)
+ */
+
+#include <asm/asmmacro.h>
+
+#ifdef MODULO
+# define OP mod
+#else
+# define OP div
+#endif
+
+#ifdef UNSIGNED
+# define SGN u
+# define INT_TO_FP(a,b) fcvt.xuf.s1 a=b
+# define FP_TO_INT(a,b) fcvt.fxu.trunc.s1 a=b
+#else
+# define SGN
+# define INT_TO_FP(a,b) fcvt.xf a=b
+# define FP_TO_INT(a,b) fcvt.fx.trunc.s1 a=b
+#endif
+
+#define PASTE1(a,b) a##b
+#define PASTE(a,b) PASTE1(a,b)
+#define NAME PASTE(PASTE(__,SGN),PASTE(OP,di3))
+
+GLOBAL_ENTRY(NAME)
+ .regstk 2,0,0,0
+ // Transfer inputs to FP registers.
+ setf.sig f8 = in0
+ setf.sig f9 = in1
+ ;;
+ // Convert the inputs to FP, to avoid FP software-assist faults.
+ INT_TO_FP(f8, f8)
+ INT_TO_FP(f9, f9)
+ ;;
+ frcpa.s1 f11, p6 = f8, f9 // y0 = frcpa(b)
+ ;;
+(p6) fmpy.s1 f7 = f8, f11 // q0 = a*y0
+(p6) fnma.s1 f6 = f9, f11, f1 // e0 = -b*y0 + 1
+ ;;
+(p6) fma.s1 f10 = f7, f6, f7 // q1 = q0*e0 + q0
+(p6) fmpy.s1 f7 = f6, f6 // e1 = e0*e0
+ ;;
+#ifdef MODULO
+ sub in1 = r0, in1 // in1 = -b
+#endif
+(p6) fma.s1 f10 = f10, f7, f10 // q2 = q1*e1 + q1
+(p6) fma.s1 f6 = f11, f6, f11 // y1 = y0*e0 + y0
+ ;;
+(p6) fma.s1 f6 = f6, f7, f6 // y2 = y1*e1 + y1
+(p6) fnma.s1 f7 = f9, f10, f8 // r = -b*q2 + a
+ ;;
+#ifdef MODULO
+ setf.sig f8 = in0 // f8 = a
+ setf.sig f9 = in1 // f9 = -b
+#endif
+(p6) fma.s1 f11 = f7, f6, f10 // q3 = r*y2 + q2
+ ;;
+ FP_TO_INT(f11, f11) // q = trunc(q3)
+ ;;
+#ifdef MODULO
+ xma.l f11 = f11, f9, f8 // r = q*(-b) + a
+ ;;
+#endif
+ getf.sig r8 = f11 // transfer result to result register
+ br.ret.sptk.many rp
+END(NAME)